The present invention relates generally to an internal combustion engine, and more specifically to a component actuation module having a fuel injection actuator, a valve actuator and a high pressure fuel components.
In conventional internal combustion engines, engine combustion valve opening and closing events are sequenced and driven by a camshaft and valve train. Such valves are typically spring biased toward a closed position and opened against the spring by a lobe on the rotating camshaft. The camshaft is synchronized with the engine crankshaft to achieve valve opening and closing at preferred times in the combustion cycle. This synchronization, or timing, is a compromise between the timing best suited for high engine speed and the timing best suited for lower engine speeds.
Fuel for such engines is often introduced into the combustion chamber using a fuel injector where the fuel mixes with intake air. Many fuel injectors and engine valves are connected through actuator various members to a cam. This connection is normally made through openings in the cylinder head. The cylinder head in-turn, covers the cylinder of the engine and is normally a unitary structure. The fuel injector and engine valve associated with each combustion chamber are connected to the cylinder head and extend into the chamber. These injector and valve actuating components are costly to manufacture and assemble.
One type of fuel injector, a hydraulically actuated electronically controlled fuel injector, is manufactured by the assignee of the present invention. The hydraulically actuated injector includes an intensifier piston that pressurizes fuel within the injector to an extremely high pressure during the injection cycle. A control valve permits high-pressure oil to controllably act on the intensifier piston of the injector. The hydraulic pressure oil, typically engine-lubricating oil acts on the injector. After the injection cycle is complete, spent oil drains from the intensifier portion of the injector drains back to an engine sump. Viscosity of the oil is highly susceptible to temperature, extreme temperatures may adversely impact control of the injection cycle. Another potential problem with using engine oil for hydraulic actuation is component wear. Contaminants in the lubricating oil may induce wear or sticking of the injector. Injector components have precise tolerances and may be highly susceptible to abrasion, it would be advantageous to actuate injectors using high quality hydraulic oil.
U.S. Pat. No. 5,237,976, issued Aug. 24, 1993 to Keith E. Lawrence discloses an engine having hydraulically actuated engine valves. An actuator housing is positioned above the cylinder head. The actuator housing includes hydraulically actuated pistons (or actuators), hydraulic rails and control valves. The actuators are electronically controlled to operate the engine valves. An injector portion of the housing controls the flow of high pressure lubricating oil to an intensifier piston positioned in the fuel injector. After the injection cycle, lubricant spills into the cylinder head and returns to the engine oil sump. The actuation module as disclosed by Lawrence reference must be assembled onto an engine for functional testing. It would be preferable, to provide an actuation module operating on a hydraulic fluid source separate from lubricating oil and being capable of testing prior to assembly on the engine.
The present invention is directed to overcoming one or more of the above identified problems.
An actuation module for use with an internal combustion engine is provided. The module includes a housing connectable to a cylinder head of an engine. At least one intensifier piston is disposed in a cavity of the module and movable between a first position and a second position. Movement toward the second position causes pressurization of fuel in a injector and an actuating valve assembly connectable to said housing directs hydraulic fluid from a hydraulic pump to the intensifier piston.
Another embodiment of the present invention provides an internal combustion engine having an engine block having a plurality combustion cylinders. A cylinder head is attached to the engine block and includes a fuel injector positioned therein. An actuation module having a piston cavity and being connectable to the cylinder head and an intensifier piston is moveably disposed within said piston cavity. Movement of said intensifier piston causes pressurization of a fuel in the fuel injector.
Another embodiment of the present invention provides an actuation module for use with an internal combustion engine. The module is connectable to a cylinder head of the engine. An intensifier piston is disposed in the housing and movable between a first and a second position. An actuating valve assembly is configured to direct hydraulic fluid to the intensifier piston causing movement of the piston, which in-turn causes pressurization of a fuel in a fuel injector. A dedicated hydraulic system provides hydraulic fluid to the actuating valve assembly.